Method for making microstructures by converting porous silicon into porous metal or ceramics

A method for making a micro structure (100) is proposed. The method starts with the step of providing a silicon substrate (102), which has a main surface. A porous silicon layer (103)—extending into the silicon substrate from the main surface—is then formed. The method continues by etching the porous silicon layer selectively to obtain a set of projecting microelements of porous silicon (112); each projecting microelement projects from a remaining portion of the silicon substrate (106), thereby exposing a corresponding external surface. The projecting microelements are then treated to obtain a set of corresponding conductive (115) or insulating (115′) microelements; each conductive or insulating microelement is obtained by converting at least a prevalent portion of the porous silicon (extending into the corresponding projecting element from the external surface) into porous metal or ceramics, respectively.